ImmGetCompositionString

ImmGetCompositionString is a function in the Microsoft Input Method Manager (IMM) API used to retrieve information about the current composition string in an input method editor (IME). The composition string represents the text that the user is actively typing and is not yet finalized. This function allows applications to access details such as the characters being composed, their attributes, and the selection range within the composition string.

When an IME is active, it intercepts keyboard input and constructs a composition string. Applications can call ImmGetCompositionString to obtain this string and its associated properties. This is crucial for providing visual feedback to the user, such as displaying the composed text in a candidate window or directly in the application's text field. The function returns a buffer containing various types of information, the specific contents of which depend on the flags passed as arguments. These flags determine whether to retrieve the composition string itself, its attributes (like color or style), or information related to selected portions of the string.

ImmGetCompositionString is typically used in conjunction with other IMM functions to manage the input process. For instance, after retrieving the composition string, an application might use ImmSetCompositionString to modify or finalize it, or ImmNotifyIME to inform the IME about changes in the application's state. Understanding and utilizing ImmGetCompositionString is essential for applications that need to integrate seamlessly with IMEs and support a wide range of input languages and methods.